This invention generally relates to an apparatus or machine for cutting stone, and more particularly to such an apparatus or machine which automatically establishes and cuts the corner lines in a piece of unfinished stone, wherein these corner lines are precisely positioned at the four corners of the finished piece of stone.
It is known in the art of stone cutting to utilize a hand measuring system to lay out or establish, in a piece of unfinished stone, the outer dimensions (i.e., length, width, thickness) of the finished stone. The finished stone may be the base stone for a graveyard headstone or monument, a bevel marker, a rock back slant marker or the headstone itself. Typically, the finished stone comprises a six-sided stone having smooth top and bottom rectangular surfaces that are parallel to each other, and four side or end surfaces that are perpendicular to both the top and bottom surfaces and to each other. The side surfaces are typically rough split to have a natural rock finish. The upright stone of a monument typically has one smooth side surface.
A common method of establishing the dimensions of the finished stone, in a larger piece of unfinished stone, is to lay out these dimensions by hand. Lines are measured and drawn in the finished stone. These lines represent the desired outer dimensions of the finished stone. The excess stone is then cut away, either by hand (e.g., with a hammer and chisel) or with a machine-operated saw. Hand-establishing the dimensions of the final piece of stone usually has involved establishing the two rectangular dimensions (i.e., length and width) on a top surface of the stone, and then transferring these dimensions through the four corner lines to the bottom rectangular stone surface. The stone is then cut along the lines to produce the finished stone.
More specifically, initially the desired position of the first long side of the rectangle on the top surface of the stone is visually established using a straightedge. Before finalizing the position of the straightedge on the top stone surface, it is necessary to check with a ruler that there is enough stone material to include the desired dimension of the second, opposite long side of the rectangle. The worker must also check that there does not exist excess stone, which necessitates moving the straightedge to "divide up" the stone to be removed. In this way, the most efficient use of the stone is made.
When the straightedge has been approximately located visually, a line is hand drawn along the straightedge, thereby establishing the first long side of the rectangle on the top stone surface. At each end of that line, measurements are made at ninety degree angles to the line. This establishes the correct width of the rectangle. The two measured locations are then marked and connected with a straightedge to establish the second long side of the rectangle on the top stone surface.
A similar hand measuring process is used to establish the two ends or short sides of the rectangle on the top stone surface. Instead of using a straightedge, a carpenter's square is typically used when marking these sides. This helps to ensure that the first end is perpendicular to the previously-marked two long sides of the rectangle. A ruler is used to determine the distance between the ends of the rectangle. After this distance has been marked, the carpenter's square is used to mark the short sides of the rectangle. The hand layout of the top stone surface is now complete. However, this process of hand measuring the top stone surface is somewhat tedious and time-consuming, and is prone to errors.
Nevertheless, once the rectangle on the top stone surface has been established, the next step is to establish the four vertical corner lines, starting at each corner of the rectangle on the top stone surface. The corner lines are typically established by removing the excess stone at the corners outside of the rectangle drawn on the top surface. Once the corner lines are established, they traverse the thickness of the stone and connect the top and bottom rectangular stone surfaces. Thus, the placement and straightness of these four vertical corner lines are crucial in accurately establishing the dimensions of the rectangle on the bottom stone surface.
This method of hand measuring the rectangles on the top and bottom stone surfaces, and the subsequent cutting away of the stone to form the corner lines, traditionally has required considerable time, effort and skill. For example, as the excess stone is trimmed away from the corners of the rectangles, the worker must frequently check the corner lines he is cutting to verify squareness with the top surface of the stone. This squareness is checked from both a long side and a short side of the rectangle using a carpenter's square. In this way, the worker can adjust the amount of stone removed. Unfortunately, the carpenter's square can fit properly on the stone only after all of the excess stone outside of each corner has been removed and the corner line has been located. The resulting corner line is rarely truly straight or square with the top and bottom stone surfaces.
Nevertheless, once the excess stone has been removed at the corner lines, the rectangle on the bottom stone surface is established by connecting adjacent vertical corner lines with a straightedge. However, the four lines defining the rectangle on the bottom surface of the stone are seldom truly parallel or perpendicular as required. This is due primarily to the cumulative errors in hand establishing the corner lines and the rectangles on the top and bottom stone surfaces.
Accordingly, it is a primary object of the present invention to provide an apparatus or machine that automatically establishes the exact size and position of the three-dimensional shape of a finished stone by accurately establishing the position of the four corner lines of the stone.
It is a general object of the present invention to establish the vertical corner lines that connect the top and bottom rectangular surfaces of a finished stone, wherein each vertical corner line is exactly square with its respective side surface, and wherein each vertical corner line is a straight line that defines the intersection of the planes of the corresponding adjacent sides of the stone.
It is another object of the present invention to facilitate and simplify the accurate location of each of the four corners of a finished stone.
Yet another object of the present invention is to significantly reduce the amount of effort, time and skill required to establish the dimensions of a finished stone.
Another object of the present invention is to accurately establish a rectangle on the top stone surface and transfer this rectangle to the bottom stone surface through the four corner lines.
Still another object of the present invention is to eliminate all steps of hand establishing any of the dimensions of a finished stone.
The above and other objects and advantages of this invention will become more readily apparent when the following description is read in conjunction with the accompanying drawings.